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Seeing hazards early: road hazards and move-over laws

General Knowledge4 minManual section 2.8.1–2.8.2

A good driver sees trouble before it happens. This lesson explains what a hazard is, why seeing it early gives you time, and which road conditions need extra care: emergency vehicles on the shoulder, work zones, pavement drop-offs, objects on the road, and ramps.

What is a hazard?

A hazard is any road condition, or any other road user, that could become a danger. Other road users include drivers, bicyclists and pedestrians.

Example: a car ahead is moving toward a freeway exit. Then its brake lights come on and it slows hard. The driver may not be sure about taking the exit and may swerve back onto the highway. That car is a hazard.

If that car really does swerve into your path, the danger is now happening: it has turned into an emergency. The difference: a hazard is a possible danger; an emergency is danger happening now.

Why seeing hazards early matters

When you spot a hazard before it turns into an emergency, you have more time to act. In the example above, you could check your mirrors, signal, and change lanes, or simply slow down, before the other car moves.

A driver who did not notice the car until it pulled back in front of him has to react suddenly. Sudden hard braking or a quick lane change is much more likely to cause a crash than a calm, planned move.

Why it matters: a heavy truck needs a long distance to stop and cannot swerve like a car. Early seeing is your main safety tool.

Move-over laws: emergency vehicles and roadside workers

More and more police officers, EMS crews, firefighters and road workers are being hit by vehicles while they work at the roadside. Many states passed move-over laws to reduce this. Where these laws exist, signs are posted on the road.

When you come up on an authorized emergency vehicle stopped at the roadside, or on a work zone:

  • Slow down and drive with caution.
  • Move over: if traffic and safety allow, change into a lane that is not next to the stopped emergency vehicle or work zone. This gives them the right-of-way and space.
  • If changing lanes is not safe, stay in your lane, slow down, and keep a safe speed for the traffic conditions.

Road hazards that call for slowing down

  • Work zones: lanes may be narrower, turns sharper, and the surface uneven. Other drivers are often distracted and drive badly. Workers and construction vehicles may move into your path. Drive slowly and carefully, and warn drivers behind you with your four-way flashers or brake lights.
  • Drop-off: sometimes the pavement drops sharply at the edge of the road. Driving too close to the edge can tip your vehicle toward the side, so the top of the truck may strike signs or tree branches. Steering can also be hard when you cross the drop-off, whether you are leaving the road or coming back on.
  • Foreign objects: things that fell on the road can hurt your tires and wheel rims, damage electrical and brake lines, or get stuck between dual tires and cause severe damage. Objects that look harmless can be dangerous: a cardboard box or a paper or cloth sack might be empty, or it might hold something heavy or solid. Stay alert so you see objects early enough to avoid them without sudden, unsafe moves.
  • Off ramps / on ramps: freeway and turnpike exits are especially dangerous for commercial vehicles. The posted ramp speed may be safe for cars but not for large or heavily loaded vehicles. Ramps that go downhill and curve at the same time are the worst, because the downgrade makes it hard to slow down, and braking while turning is risky. Get your speed low enough before you reach the curved part of the ramp.
Check your state

Move-over laws are state laws and the details (how much to slow, which vehicles count) differ. Check your state manual.

References and scope

The topic reference is listed below. Sources support verification; the lesson itself is here. The current content needs technical and language review before public launch.

Manual reference: 2.8.1–2.8.2

Put it into practice

Educational questions with explanations. The answer review also works without the interactive quiz.

Preparing your questions…

Review questions with answers

  1. What is a hazard?
    1. Any crash that has already happened
    2. A road sign that warns of a curve
    3. Any road condition or road user that could be a danger
    4. Any vehicle that is driving faster than you
    Show answer
    Any road condition or road user that could be a danger

    A hazard is any road condition or other road user (driver, cyclist, pedestrian) that is a possible danger.

  2. A car slowing near an exit suddenly cuts back in front of you. At that moment it has become:
    1. An emergency
    2. A minor hazard
    3. A conflict that is already solved
    4. A normal lane change
    Show answer
    An emergency

    When the hazard actually cuts in front of you, it is no longer just a possible danger; it is an emergency.

  3. Why is it important to see hazards before they become emergencies?
    1. So you can sound your horn longer
    2. So you can drive faster past them
    3. So you do not need to use mirrors
    4. So you have time to act calmly instead of suddenly
    Show answer
    So you have time to act calmly instead of suddenly

    Seeing hazards early gives you time to check mirrors, signal, change lanes or slow down. Sudden braking or swerving is much more likely to cause a crash.

  4. Which reaction is MOST likely to lead to a crash?
    1. Slowing down early when you see a hazard
    2. A sudden hard brake or quick lane change
    3. Checking your mirrors before a lane change
    4. Signaling well before changing lanes
    Show answer
    A sudden hard brake or quick lane change

    Sudden moves give other drivers no warning and can make you lose control. Planned, early moves are safer.

  5. You see a police car stopped on the shoulder with lights flashing. If it is safe, you should:
    1. Keep your speed and lane
    2. Speed up to pass quickly
    3. Slow down and move to a lane not next to the police car
    4. Stop in your lane behind the police car
    Show answer
    Slow down and move to a lane not next to the police car

    Move-over laws require you to slow down and, when safe, change into a lane not next to the stopped emergency vehicle.

  6. You approach a work zone, but traffic makes a lane change unsafe. What should you do?
    1. Stay in your lane, slow down, and keep a safe speed for conditions
    2. Change lanes anyway because the law requires it
    3. Stop completely until the lane next to you is empty
    4. Use the shoulder to get around the work zone
    Show answer
    Stay in your lane, slow down, and keep a safe speed for conditions

    If moving over is not safe, slow down and proceed with caution at a safe speed for traffic conditions.

  7. When driving through a work zone, how can you warn drivers behind you?
    1. Flash your high beams at them
    2. Sound your horn continuously
    3. Turn on your interior cab light
    4. Use your four-way flashers or brake lights
    Show answer
    Use your four-way flashers or brake lights

    Drive slowly near work zones and use four-way flashers or brake lights to warn the drivers behind you.

  8. Driving too close to a sharp pavement drop-off at the road edge can:
    1. Improve traction on the right tires
    2. Tilt the vehicle so its top may hit signs or tree limbs
    3. Cause the brakes to get wet
    4. Make the vehicle easier to steer
    Show answer
    Tilt the vehicle so its top may hit signs or tree limbs

    A drop-off can tip the vehicle toward the roadside, so the top can strike roadside objects, and steering across the drop-off is hard.

  9. You see an empty-looking cardboard box in your lane. What is the best way to think about it?
    1. It is harmless, so drive over it
    2. It is safe to straddle it with your dual tires
    3. It may contain something heavy; avoid it without sudden, unsafe moves
    4. Brake hard immediately to stop before it
    Show answer
    It may contain something heavy; avoid it without sudden, unsafe moves

    Boxes and sacks may hold heavy or solid material. See objects early so you can avoid them without sudden, unsafe moves.

  10. Objects that fall on the road can get caught between dual tires and cause:
    1. Severe damage
    2. Better braking
    3. Lower tire temperature
    4. Higher fuel economy
    Show answer
    Severe damage

    Foreign objects can damage tires, rims, electrical and brake lines, and cause severe damage when caught between duals.

  11. The speed limit posted on an off ramp:
    1. Is the minimum speed for trucks
    2. Always applies to heavy vehicles only
    3. Is set for trucks, so cars should go slower
    4. May be safe for cars but too fast for large or heavily loaded vehicles
    Show answer
    May be safe for cars but too fast for large or heavily loaded vehicles

    Ramp speeds may be safe for cars but not for larger or heavily loaded vehicles.

  12. Which kind of exit ramp is especially dangerous for a commercial vehicle?
    1. A straight, level ramp
    2. One that goes downhill and curves at the same time
    3. One with a long acceleration lane
    4. One with a posted speed limit
    Show answer
    One that goes downhill and curves at the same time

    A downhill curve makes it hard to slow down, and braking while turning is risky.

  13. Before you reach the curved part of an off ramp you should:
    1. Already be going slowly enough
    2. Shift to neutral to coast
    3. Speed up to keep momentum
    4. Brake hard in the middle of the curve
    Show answer
    Already be going slowly enough

    Make sure you are slow enough before entering the curve; braking and turning together is dangerous.

  14. In a work zone, other drivers tend to drive more safely than usual. True or False?
    1. True
    2. False
    Show answer
    False

    False. Other drivers in work zones are often distracted and drive unsafely, so you must be extra careful.